It depends. Are you viewing it as HTML? Do you have JavaScript enabled globally?
If the answer is yes it's theoretically possible that just the act of opening it could be enough.
You can be surfing the web, visit a site and if you have JS enabled possibly be the victim of a drive-by download where you don't have to click on anything, just open the site in your browser.
Nothing can take the place of educating yourself to the possibilities, taking necessary step to protect yourself by locking down your browser and controlling your clicking finger.